1. Field of the Invention
The present invention relates to a contact strip for an electrical connector, and particularly to a contact strip with plural contacts thereon for resiliently contacting with a mother board and a daughter board that are oriented perpendicularly to each other, wherein the contact strip has an arrangement between a carrier of the strip and the contacts which can ensure that there is no remnant left on each contact when the carrier is separated from the contacts.
2. Description of Related Art
Electronic systems, such as computers, often employ electrical connectors to interconnect two electronic sub-systems. To meet the trend of miniaturization of computer technology, the electrical connectors are developed to have a compact arrangement regarding contacts of the electrical connectors. The contacts are commonly stamped from a metal sheet and interconnected by a carrier. The carrier is then severed from the contacts after the contacts are completely inserted into a connector housing.
U.S. Pat. No. 5,071,371, assigned to Molex Incorporated, discloses a card edge connector having a contact strip. The connector comprises a connector housing defining a cavity and a plurality of slots therein, and a plurality of contacts received in the slots. Each contact includes a base interferentially received in the slot, a contact portion extending into the cavity for electrically engaging with a daughter board which is received in the cavity of the connector housing, and a tail extending beyond a mounting face of the connector housing for electrically connecting to a mother board via through hole technology. Therefore, an electrical connection is established between the mother board and the daughter board.
The contacts of the connector are stamped from conductive material and interconnected by a carrier to thereby form the contact strip. The tail of each contact is connected with the carrier. In assembly, the contacts are simultaneously inserted into the slots of the connector housing. The carrier is then severed from the contacts via a horizontal V-cut in the tail which is perpendicular to an extending direction of the tail. However, when the tails of the contacts are required to resiliently engage with the mother board, the V-cut design of this prior art is difficult in fulfilling the requirement of having smooth free ends for the tails.
U.S. Pat. No. 4,780,095, assigned to Digital Equipment Corporation, discloses a card edge connector having plural contacts and addresses to the problem encountered by the ""371 patent. As shown in FIGS. 1-4 of the ""095 patent, the contacts 14 are profiled out of a section of a flat stock. Each contact 14 includes a stabilizer plate 26 with a root section 28 positioned within a slotted root nesting area 30 of an insulator body 12, a daughter contact beam 36 upwardly extending from an intermediate location on the stabilizer plate 26 with a contact area 40 projecting into a board slot 20 for electrically engaging with an inserted daughter board. A surface pressure contact beam 32 extends downward from the stabilizer plate 26 and toward the root section 28. The surface pressure contact beam 32 has a curved portion (not labeled) connecting with the stabilizer plate 26 at a portion distal from the root section 28, and a surface pressure contact 34 at a free end thereof for resiliently contacting with a contact pad on a mother board.
Referring again to FIG. 4 of the ""095 patent, during the stamping process, two adjacent contacts 14 are interconnected via a connecting portion (not labeled) between the curved portion of the contact 14 and the root section 28 of an adjacent contact 14. Subsequently, the contacts 14 can be excised from the flat stock at the connecting portions. However, the contact 14, which is severed from the flat stock, has a scrap (not labeled) left on the curved portion. The scrap may affect the flexibility of the surface pressure contact beam 32 of the contact. As a result, the electrical connection between the connector and the mother board may be unreliable.
Other related contact strips for electrical connectors are described in U.S. Pat. Nos. 6,379,161, 6,083,060, 5,860,821 and 4,428,642.
Hence, there is a need to have an improved contact strip which can solve the problem of the related art.
Accordingly, it is an object of the present invention to provide a contact strip wherein each contact separated therefrom has a good flexibility for ensuring a reliably compressive engagement between the contacts and a printed circuit board.
It is another object of the present invention to provide a contact strip with plural contacts thereon for compressively connecting with a printed circuit board wherein each contact is easily separated from a carrier of the contact strip and has no remnant left thereon when the contacts are separated from the carrier.
In order to achieve the objects set forth, a contact strip in accordance with the present invention includes a plurality of contacts interconnected by a carrier. Each contact includes a body portion, an upper arm upwardly extending from the body portion for engaging with a first printed circuit board and a lower arm extending downwardly and laterally from the body portion. The lower arm has a free end for resiliently engaging with a second printed circuit board and a connecting portion connecting with the body portion.
The carrier has a plurality of connection stems each connecting with the connecting portion of a corresponding contact. An oblique score is defined between the connecting portion of each contact and a corresponding connection stem of the carrier for facilitating removing the carrier from the contacts. There is no remnant left on the connecting portion of the lower arm when the contact is separated from the carrier, whereby the flexibility of the lower arm is ensured.